Distributed ecohydrological modelling to evaluate irrigation system performance in Sirsa district, India II. Impact of viable water management scenarios

This study focuses on the identification of appropriate strategies to improve water management and productivity in an irrigated area of 4270 km2 in India (Sirsa district). The field scale ecohydrological model SWAP in combination with field experiments, remote sensing and GIS has been applied in a distributed manner generating the required hydrological and biophysical variables to evaluate alternative water management scenarios at different spatial and temporal scales. Simulation results for the period 1991–2001 show that the water and salt limited crop production is 1.2–2.0 times higher than the actual recorded crop production. Improved crop husbandry in terms of improved crop varieties, timely sowing, better nutrient supply and more effective weed, pest and disease control, will increase crop yields and water productivity in Sirsa district. The scenario results further showed that reduction of seepage losses to 25–30% of the total canal inflow and reallocation of 15% canal water inflow from the northern to the central canal commands will improve significantly the long term water productivity, halt the rising and declining groundwater levels, and decrease the salinization in Sirsa district.